Operating income estimation: based on the estimated unit price and estimated sales volume of related products in each year during the project operation period. In the case of calculating cash discounts and sales discounts by the total price method, operating income refers to the net amount after deducting discounts and discounts. Estimation of salvage value of recovered fixed assets: it is assumed that the depreciation period of fixed assets is equal to the production and operation period. Therefore, for the projects under construction, as long as the original value of fixed assets is multiplied by its legal net residual value rate, the residual value of recovered fixed assets at the end can be estimated; The balance of fixed assets recovered in advance during the production and operation period can be estimated according to its estimated net salvage value. For the renovation project, two estimates are needed. The first estimate: the recovery balance at the beginning of the construction period, that is, the net realizable value of the old equipment sold in advance. Second estimation: estimate the recovery balance of the terminal according to the construction project method.